BABCOCK UNIVERSITY COURSE CODE: MLSC 202 LECTURE TOPIC: HISTORY AND EVOLUTION OF MICROBIOLOGY

1. BABCOCK UNIVERSITY COURSE CODE: MLSC 202 LECTURE TOPIC: HISTORY AND EVOLUTION OF MICROBIOLOGY

2. Lecture Objectives • At the end of the lecture, the student should be able to: • Define medical microbiology • Name 4 pioneers of science of microbiology • List the landmark discoveries in the evolution of microbiology

3. WHAT IS MICROBIOLOGY? • The study of microorganisms and their activities: Nutrition, multiplication, pathogenicity control, etc. • WHAT ARE MICROORGANISMS? • They are very minute organisms that are too small to be seen with the naked eye. They are also referred to as microbes. • They are observed with the of a magnifying device called the microscope.

4. WHAT IS MEDICAL MICROBIOLOGY • The study of disease causing microorganisms with respect to man. • Disease caused by a microorganism is called “infectious disease” or simply, “infection”. • Differentiate disease from infection!! • The more we know of microorganisms, the more the quality of human life is improved.

5. EVOLUTION AND HISTORY OF MICROBIOLOGY • The science and evolution of microbiology is an interesting chronicle of man’s indomitable spirit to conquer. • The history is loaded with landmark breakthroughs of early scientists that has made microbiology one of the most applied sciences. • Prior to the discovery of microorganisms, there were two kingdoms of living things: Plant and animal.

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7. Brief History • Prior to the discovery of microorganisms, there were two kingdoms of living things: Plant and animal. • 1675: Anthony van Leeuwoenhoek, a Dutch draper, described the “little animals” (animacules) he observed with his crude home made microscope while examining rain water and watery infusions. • He was the first man to describe microorganisms.

8. Controversy similar to one concerning the origin of life was witnessed in the case of the origin of microorganisms. • The theory or concept of “spontaneous generation” was put forward and believed by many scientists for centuries. • The belief in the spontaneous generation of life from nonliving matter was introduced by Aristotle, who lived around 350 BC.

9. They believed that life arose spontaneously from pre-existing life and so the term “abiogenesis”. • This belief remained unchallenged for more than 1000 years. • Meanwhile, there were opponents of this idea. The controversy was on for over 1000 years. • Until in 1868, an Italian scientist, Francesco Redi, after many smart experiments, disproved theory of abiogenesis.

10. Spontaneous Generation DebateFrancesco Redi- Experiments on Flies First to formally challenge the accepted belief of spontaneous generation. • Redi's Question: Where do maggots come from? • Hypothesis: Maggots come from flies. • Experiment:Redi put meat into three separate jars.

11. Jar-1 • Left open • Maggots developed • Flies were observed laying eggs on the meat in the open jar • Jar-2 • Covered with netting • Maggots appeared on the netting • Flies were observed laying eggs on the netting • Jar-3 • Sealed • No maggots developed

12. Spontaneous Generation DebateAnton van Leeuwenhoek’s “Animalcules” • As a draper(merchant who sells cloth and dry goods), he used lenses to examine cloth. This probably led to his interest in lens making. • He assembled hundreds of microscopes, some of which magnified objects 270 times. • As he looked at things with his microscopes, he discovered “micro” organisms - organisms so tiny that they were invisible to the naked eye. • He called these tiny living organisms “animalcules” (little animals). He first described bacteria, protozoans and many cells of the human body.

13. He communicated his observations in writing to the Royal Society of Academy, London. • Robert Hooke, an English man, was the first to observe microorganisms with his own crude microscopes. He was in the committee to validate the observations of Leeuwenhook.

14. The Controversy Over Spontaneous GenerationJohn Needham & LazzaroSpallanzani The Question: What causes tiny living things to appear in decaying broth? • Needham’s Hypothesis: Spontaneous generation. • Spallazani’s Hypothesis: Microbes come from the air. Boiling will kill them.

15. Louis Pasteur (1822-1895), a French chemist ( to some people, he is the father of medical microbiology and to others, of modern medicine), performed series of brilliant researches and experiments for the wine industry between1860 and1890. • Louis Pasteur performed several ground breaking experiments that indeed showed the applicability of microbiology in various aspects of human life. • His notable contributions include:

16. He was able to debunk the spontaneous generation hypothesis. • In collaboration with other scientists, established the “germ theory of disease” • He described vaccine and vaccination to protect against microbial activity.

17. He established the principles of immunisation following the work of Edward Jenna in 1766. • He devised a method of preventing the growth of microorganisms (pasteurization) • He collaborated with John Tyndall (1820-1883) a physicist who established that microorganisms are killed by free steaming (Tyndallization), to convince others about fallacy of abiogenesis and autothencity of biogenesis.

18. Joseph Lister, Professor of surgery in Glasgow, applied Pasteur’s observations to the prevention of wound sepsis. • In 1867, he discovered the use antiseptic technique to kill bacteria in wound and air with carbolic acid. • Robert Koch (1843-1910) (father of medical microbiology/bacteriology), a German scientist, through his work established the veracity of the germ theory of disease.

19. He was a contemporary and later rival of Louid Pasteur. • With his colleague, Ehrlich (who worked on dyes), they were able to stain bacteria and viewed under the microscope. • He introduced agar as gelling agent for culture media. He was the pioneer in laboratory techniques. ( Petri dish named after his assistant, Richard Petri).

20. He discovered and worked on causative microorganisms of anthrax and tuberculosis among others. • He enunciated the famous four Koch’s postulates to confirm the relationship between infectious disease and microorganisms: • 1. The organism must be found in every case of the disease. • 2. The organism must not be found in a healthy person.

21. 3. The organism must be isolated and grown in pure culture. • 4. Inoculation into a susceptible animal should reproduce the disease and the organism isolated from the animal. • 5. (Added later) Infection should produce circulating antibody specific for the infecting organism (antigen).

22. It is obvious now with current knowledge that all the postulates are not applicable in every disease condition. • CONFUSION: • Ins-pite of the tremendous progress made, there was still confusion. • Living things then belonged to Animal kingdom or Plant kingdom • In which kingdom to place these microorganisms?

23. 1866: Hackelproposed the creation of a third kingdom – the Protista • Protista included: algae, protozoa, fungi, bacteria and viruses. • 1957: Stanierdivided Protista into Eukaryotic (higher) cells and Prokaryotic (lower) cells. • To minimise the confusion, microbiology was broken into Bacteriology, Virology, Parasitology and Mycology.

24. INTRODUCTION TO HISTOPATHOLOGY • Definitions • Pathology: Study of diseases or the changes that occur from diseases. Clinical pathology refers to pathology in living persons. • Histology: The study of tissue structure and microscopical appearances of body tissues. • Histopathology: the study of diseased tissues.

25. Anatomy: The study of the structure of the body. • Morbid anatomy: the study of diseased body parts. • Cytology: The study of cells or cellular structure • Cellular pathology: the study of diseased cells of the body.

26. - Exfoliative cytology: Study of cells that have been shed. • Histopathology is also referred to as Morbid anatomy, cellular pathology etc.